Human placental membrane (e.g. amniotic membrane) has been used for various types of reconstructive surgical procedures since the early 1900s. The membrane serves as a substrate material, more commonly referred to as a biological dressing or tissue graft. Such a membrane has also been used for ophthalmic procedures and more recently for dental regenerative procedures, treating ulcers, and as an adhesion barrier. Typically, the membrane is either frozen or dried for preservation and storage.
Placental tissue is typically harvested after an elective Cesarean surgery. The placenta is composed of the amniotic sac and sometimes is meant to include the umbilical cord and amniotic sac. The amniotic sac contains the amniotic fluid and protects the fetal environment.
The amniotic sac, commonly referred to as the amniotic membrane, has two primary layers of tissue, amnion and chorion which are separated by a thin connective layer which is sometimes referred to as the intermediate layer. Amnion is the innermost layer of the amniotic sac and is in direct contact with the amniotic fluid. Histological evaluation indicates that the membrane layers of the amnion consist of a single layer of epithelium cells, thin reticular fibers (basement membrane), a thick compact layer, and a fibroblast layer. The fibrous layer of amnion (i.e., the basement membrane) contains collagen types IV, V, and VII, and cell-adhesion bio-active factors including fibronectin and laminins.
Placental tissue, such as amnion membrane, provides unique characteristics when used for surgical and wound-healing procedures, including providing a matrix for cellular migration/proliferation, providing a natural biological barrier, is non-immunogenic, and contains numerous bio-active molecules. Placental tissue can be used as a membrane to assist in tissue regeneration and improved healing outcomes in numerous applications. The amnion has the capability to self-adhere or, in the alternative, is susceptible of being fixed in place using different techniques, including fibrin glue or suturing.
Placental tissue grafts have been used in a variety of medical applications, including wound care and cosmetics. However, these tissue grafts lack flexibility and/or coherency especially in environments where shear is common. Accordingly, there is a need to provide placental tissue compositions with enhanced flexibility and/or coherency.
Micronized placental tissue components have been previously disclosed and used in an aqueous suspension for injection into injured body components such as tendons, ligaments, etc. However, notwithstanding the beneficial properties imparted in healing such injuries, it would be desirable to provide for a composition which retains its position once injected into the body.